The present invention relates to an apparatus and method for securing horizontally loaded cargo units to a vessel.
As known in prior art, units moving on wheels are secured on a horizontally loaded vessel, in particular semitrailers, rolltrailers and cassettes are secured on a ro-ro vessel, by using different chains, webbings and wires, by means of which each cargo unit is fastened to the deck of the vessel. One problem in using chains, webbings and wires for lashing the cargo unit to the deck of the vessel is that, when these are used, the unit lashed to the deck together with lashings and the deck structure does not necessarily always form a continuous structure of sufficient strength, which might result in the shifting of cargo in the cargo space in case the number or the quality of lashings is inadequate. A problem with these known lashings is also that the lashing is done by hand, which is in itself rather expensive and time-consuming.
As known in prior art, the vessel and the cargo unit are usually parallel, in which connection the forces which are caused by the movements of the vessel and which are directed at the cargo are greatest in the transverse direction, which means that transverse securing is very important when cargo units are lashed to the vessel. Safety factors are also important, and when chains, webbings, wires, etc. known from prior art are used, one problem is that it is possible to fit them in a wrong manner, in which connection the lashing does not necessarily fulfil the function set for it.
As known in prior art, in addition to chains, webbings, etc., a trestle, or a trailer horse, is used in connection with securing of semitrailers, the wheelless end of the semitrailer being supported by means of the trestle for the time of transport on the vessel. Semitrailers are conventionally provided with their own legs, by means of which the wheelless end can be supported ashore, but these legs do not alone sustain the load which is directed at them from the unit and its cargo during sea transport as a result of the movements of the vessel, and thus said trestle or equivalent is needed for support of the semitrailer during sea transport. The trestle is usually made of steel and it is placed manually under the wheelless end of the semitrailer.
With respect to the prior art relating to the invention, reference may be made, for example, to the magazine article xe2x80x9cCorthons nya skogsprodukifanyg specialutrustade f{dot over (o)}r kassetterxe2x80x9d, Svensk Sjxc3x6farts Tidning 46, from the year 1994, page 18, which describes a cassette ship in which units specially designed for this purpose, cassettes, are supported on one another in the transverse direction. This prior-art arrangement suffers, however, from the problem that the unit is not secured to the vessel and that the cargo space of the vessel shall be dimensioned and constructed such that it is suitable for support of cassette units. The supporting method can be used only for units designed for this purpose.
U.S. Pat No. 3,603,544 discloses one solution for securing semitrailers, in which a box is placed under the wheelless end of a semitrailer, which box is coupled to the kingpin of the semitrailer and which is screwed in an internally threaded hole located in the deck. In the arrangement in accordance with U.S. Pat No. 3,603,544 there is a kingpin beneath the top plate for coupling a tractor, and the top plate comprises a locking arrangement by which it is connected to a semitrailer. A problem in this known arrangement is that decks of the vessel contain a large number of holes which shall be kept clean, which is rather troublesome and causes a large number of cleaning operations.
One solution representing prior art is described in the international patent application PCT/SE 97/00381, (WO 97/30890), which discloses a method and a device for loading, securing and unloading semitrailers, which method employs a box-like trestle-type of support means for a semitrailer, which means comprises parts for supporting the front part of the semitrailer, a coupling member provided on the trestle which is coupled to the fifth wheel of a tugmaster, and the support further comprises members for fastening the trestle to the kingpin of the semitrailer, and at least one locking device by means of which at least one of several predetermined locking points is secured to a deck of a cargo space of a vessel. A problem with this prior art arrangement is constituted by the holes which are located in the deck and which are needed for securing, the cleaning of said holes being problematic. Moreover, this known arrangement is suitable only for a vessel constructed for this purpose because the vessel must be provided with locking holes in the deck for the securing trestle locations. Since the units which are secured are not necessarily equal in length, in order to avoid a waste of space, the number of holes required is far higher than the number of holes used at each particular time. The provision of such an arrangement for new ships is expensive and for old ships very expensive. This known arrangement is also expensive to build and requires a lot of maintenance because of the complicated mechanism used in locking it to the deck.
When handling a unit moving in a horizontal plane, for example, a trailer, rolltrailer, etc., it is essentially important in securing the cargo unit on a vessel that it could be locked to the vessel such as to achieve a continuous structure that is as rigid as possible. Thus, one object of the invention is to provide an arrangement which when it is used allows securing to be accomplished such that the cargo unit forms a rigid continuous structure together with the vessel, and also to provide a securing system by means of which the movements of the cargo unit secured are prevented transversely in particular but also longitudinally with respect to the sailing direction of the vessel.
An object of the invention is also to provide a securing arrangement which is suitable for use in connection with all types of vessels loaded horizontally, both new vessels and those already in service, in particular ro-ro vessels.
A further object of the invention is to provide an arrangement by means of which a semitrailer can be supported and secured on a ship such that the securing arrangement forms a rigid continuous structure and its use is easy, simple and safe.
A particular further object of the invention is to provide a trestle which is suitable for use in many types of cargo-carrying vessels to serve as a trestle used in connection with securing, handling and supporting of semitrailers, and which allows supporting and securing to be accomplished reliably, and the use of which in connection with a tugmaster is easy, and which does not require any special arrangements on a ship""s deck or the arrangements to be made for it can be accomplished economically both on old and new vessels.
With a view to achieving the objectives stated above as well as those that will come out later, the method according to the invention is mainly characterized in what is set forth in the characterizing clause of claim 1.
The device according to the invention is in turn mainly characterized in what is set forth in the characterizing clause of claim 9.
By means of the securing element in accordance with the invention, a cargo unit moved in the horizontal plane: for example, a trail, a rolltrailer, or a cassette can be locked to a vessel such that a rigid continuous structure is achieved, which can be considered a solution that is technically superior to the lashing of a cargo unit known from the current state of the art. A first securing part formed by a rail extending in the longitudinal direction with respect to the loading direction of the units is fitted onto a bulkhead of a vessel and a second securing part formed by a mating rail or hook is fixed to the cargo unit, which second securing part can be locked to the rail fitted onto the vessel. The securing parts form a securing element. The section of the securing element forms a geometric form such that the parts of the element cannot be detached from each other without substantial deformation. By means of the securing arrangement in accordance with the invention, it is thus possible to prevent transverse movements in particular with respect to the sailing direction of the vessel, and the locking arrangement also advantageously comprises locking parts which prevent the movement of the secured unit in the longitudinal direction and in the vertical direction.
Securing elements are also formed between the cargo units in such a way that there is one securing part on either longitudinal side of the cargo unit, which securing part is structured and arranged to correspond to the shape of the securing part located on an adjacent cargo unit or on the bulkhead of the vessel such as to provide a securing element forming a securing arrangement, said securing element being located on the longitudinal side of the cargo unit and, similarly, on the longitudinal bulkhead of the vessel or on the longitudinal side of an adjacent cargo unit. Locking parts or equivalent are advantageously formed in connection with the securing element for preventing said securing element from being opened in the longitudinal and the vertical direction. The part of the securing element which is mounted on the bulkhead of the vessel can be replaced, when needed, for example, in old vessels, with a sufficient number of chains and equivalent known from prior art.
This invention is suitable for use in connection with securing cargo units which are loaded horizontally onto a vessel, in particular rolltrailers, cassettes, semitrailers and similar types of cargo units. In this description, a cargo unit refers to a rolltrailer, a cassette and/or a semitrailer with their cargoes, and in connection with semitrailers, the cargo unit also includes a trestle intended for supporting and securing the semitrailer.
The securing element is formed of two securing parts which are located on two adjacent cargo units or on a cargo unit and a bulkhead of a vessel, which securing parts when connected to each other constitute an interlocking coupling such that the cargo remains in place when the vessel is sailing. In connection with the securing element, locking parts are provided on the adjacent cargo units or on the cargo unit and on the bulkhead of the vessel adjacent to it in order to prevent longitudinal and vertical movement of the cargo unit.
In accordance with an advantageous embodiment of the invention, the trestle used for supporting and securing a semitrailer comprises securing parts on both sides in order to form a securing element in accordance with the invention, whereby the trestle can be reliably secured to the vessel. Adjacent trestles have securing parts for securing them to each other and, in addition, the trestle comprises means for coupling it to a tugmaster and to a semitrailer.